Device for removing individual sheets from a stack



M y 7 ZOGLMANN 3,511,496

Filed May 23, 1968 DEVICE F012 REMOVING INDIVIDUAL SHEETS FROM A STACK 2She sis-Sheet 1 TNVENTOR fin o 4 F Zwl/M lvA/ ATTORNEY Melly 1 2, Ifz'bsLMANN DEVICE FOR RE OVING 'mnxvibuAL srmms FROM A STACK, 7 Filed may23. 1968 2 Sheets-Sheet 2 INVENTOR ATTORNEY United States Patent US. Cl.271-37 3 Claims ABSTRACT OF THE DISCLOSURE A device for removingindividual relatively stiif sheets from a supply of sheets, stacked in abox whose bottom is convex in one direction. Hooked fingers overlappingthe upper sheet of the stack are provided at the discharge end of thebox and are reciprocally movable along the sheet edge. The fingerscooperate with perforations in the sheet edges which, for successivesheets, are laterally displaced with respect to each other so that onlyone sheet at a time is released by the fingers. A revolving hollowcylinder with a longitudinal slot is placed over the discharge end topick up the lifted sheet edge.

The invention relates to a device for removing individual sheets from astack, comprising a supply box with a bottom curved in one directionwhich carries the stack of sheets, and means for separating theuppermost sheet from the stack so far as to present an edge of thissheet to a system of transport rollers.

Prior art devices of this type generally comprise a tub-- ber rollerwhich is arranged for reciprocal movement on the uppermost sheet. Duringthe forward movement the roller is blocked so as to remove thisuppermost sheet by friction. During the return stroke the roller is freeto rota-te.

A drawback of this device, when used for sensitive sheet material suchas photographic films, is that the surfaces of these sheets may sufferfrom excessive friction between the successive sheets. Another drawbackmay arise when the sheets are sticking together so strongly that theyare not readily separated by the movement of the rubber roller. In thatcase two or more sheets may be removed from the stack at a time andpresented together to the transport rollers, where no means areavailable to separate such sheets.

It is an object of the invention to avoid these drawbacks of the priorart devices. For that purpose the device according to the invention hasat least one finger overlapping the edge of the uppermost sheet at thedischarge end of the supply 'box and pressing the stack against thebottom of this box which is convex. The finger is reciprocally movablealong the sheet edge so as to be brought into registry with aperforation of the edge. Per forations of the successive sheets of thestack are laterally displaced with respect to each other, so that onlythe uppermost sheet, by its inherent stiffness, is permitted to lift itsedge from the stack when the finger reaches the perforation thereof,whereas the remainder of the stack is held pressed by the finger againstthe convex bottom of the supply box. By thus taking advantage of theinherent stiffness of the sheets it is made certain that only one sheetat a time is released from the stack and no intensive friction betweenthe successive sheets is created.

According to the invention the released sheet may be further removedfrom the stack by a revolving hollow cylinder with a longitudinal slot,which cylinder is so positioned over the discharge end of the supplybox, that 3,511,496 Patented May 12, 1970 "ice the edge of the releasedsheet is forced to slip into the longitudinal slot as it passes by.Thereafter the sheet edge is further lifted by one edge of thislongitudinal slot and picked up by counter rollers cooperating with thehollow cylinder to be finally removed from the box. In order to preventthe released sheet edge from slipping out of the longitudinal slotbefore it reaches the counter rollers, the curved bottom of the supplybox may by preference be convex only in the region near the dischargeend of the device, but concave for the remaining part. This results in afurther stretching of the released uppermost sheet while it is beinglifted by the slot, thus forcing the sheet edge deeper into the hollowcylinder.

The invention will be described in greater detail with reference to thedrawing, in which:

FIG. 1 is a perspective view of a device according to the invention;

FIG. 2 is a cross-sectional view of the device;

FIG. 3 is a perspective view of a part of the device, seen from the samedirection as FIG. 1.

FIG. 1 shows a supply box having sidewalls 1 and 2 and a curved bottom3. Bent strips 4 project from the rear edge of that bottom while at thedischarge end of the box an elongated panel 5 carrying a pair of hookedfingers 6 is reciprocally movable, as indicated in the drawing byarrows. A stack of sheets which have to be removed individually isfirmly held between the strips 4 and the fingers 6 so as to conform tothe partly convex and partly concave curvature of the bottom 3. Thisbottom is hinged on a shaft 7.

As seen in FIG. 2 a shaft 8 bearing in the sidewalls 1 and 2, isprovided with fixed arms 9 and 10. Arm 9 carries a roller 11 which isurging the discharge end of the bottom 3 upwards under the action of adrawing spring 12, connected to the arm 10. Thus, the bottom 3 at thedischarge end is raised slightly each time a sheet 13 is removed fromthe stack in the supply box, thus pressing this stack against thefingers 6 once more.

As seen in FIG. 3, the sheet edges at the discharge end of the box areprovided with V-shaped perforations. In the described embodiment everysheet has two such perforations of which the left ones only are visiblein FIG. 3. The perforations of the uppermost sheet and of the next sheetare designated 30 and 30', respectively. They are laterally displaced asmall distance with respect to each other, and so are the perforationsin each successive pair of sheets which alternately correspond inposition to perforations-30 and 30'. The elongated panel 5 isreciprocally movable along the guiding rods 14 and 15 and has twoshoulders 16 and 17. In the non-operative state of the device a lever 18rests against the shoulder 17 keeping the panel 5 in the position shownagainst the action of the drawing spring 19. A hollow rotatable cylinder20 positioned just over the discharge end of the stack has alongitudinal slot with. edges 21 and 22. This cylinder, which may bedriven by any conventional means (not shown), is secured to a shaft 23which also carries a bevel gear wheel 24. The rotation of the cylinder20 is transferred through a bevel gear wheel 25 on a shaft 27 to a disc26. An eccentric pin 28 on the disc 26 cooperates with a block 29secured to the bent end of panel 5. As long as the device is in rest thepin 28 engages the block 29 only during a small fraction of eachrevolution, viz each time the pin comes at the shortest distance to thesidewall 1. The lever 18 has a fixed pivot 31. When sheets have to beremoved, this lever is slightly lifted counter-clockwise. Shoulder 17 isset free thereby and the panel 5 is pulled to the left by the drawingspring 19 until it is stopped by the shoulder 16 engaging the lever 18.At this moment the fingers 6' are in registry with the perforations ofthe uppermost sheet 13 of the stack. The uppermost sheet is no longerheld by the fingers and the forward end of that sheet is urged againstthe hollow cylinder 20 which is rotating clockwise, When the leadingedge 22 of the longitudinal slot in this cylinder has passed along theedge of sheet 13, the latter slips into the cylinder after which it islifted by the trailing edge 21 of the slot. Simultaneously with thislifting action the concave portion of the released sheet 13 will alsostretch to some extent. As a result of this the sheet edge slips deeperinto the cylinder thus preventing the sheet edge from slipping out. Whenthe cylinder 20 revolves on, the sheet -13 touches the counter rollers32 which, in cooperation with the cylinder 20, remove the sheet from thesupply box. It will be noted that the trailing edge 21 of the slot has arecessed portion between the counter rollers 32. This is to ensure thata released sheet 13 which might have a somewhat corrugated edge enterswith certainty into the longitudinal slot.

In the meantime the pin 28 has pushed the panel back to the rightagainst the action of the drawing spring 19. At the end of this movementthe fingers 6 are in registry with the perforations 30' of the nextsheet. The edge of this sheet is released and will be lifted by the edge21 of the longitudinal slot as explained herebefore. The removal of theindividual sheets will automatically be continued in this way untillever 18 is brought back to the inoperative position shown in FIG. 3. Ofcourse, lever 18 can only return to that position when panel 5 is in theextreme right-hand position, enabling the lever to fall behind theshoulder 17.

What I claim is:

1. A device for removing individual sheets from a stack of sheets,comprising a supply box with a bottom curved in one direction whichcarries the stack of sheets, and means for separating the uppermostsheet from the stack so far as to present an edge of that sheet to asystem of transport rollers, characterized in that it comprises at leastone finger overlapping the edge of the uppermost sheet on the dischargeside of the supply box and pressing the stack against the bottom of thatbox, which is convex, said finger being reciprocally movable along saidsheet edge so as to be brought into registry with a perforation of saidsheet edge, perforations of successive sheets of the stack beinglaterally displaced with respect to each other, whereby the uppermostsheet is permitted to lift said sheet edge from the stack by itsinherent stiffness when said finger reaches the perforation thereof, andthe remainder of said stack is held pressed by said finger against saidconvex bottom.

2. The device of claim 1 further comprising a revolving hollow cylinderwith a longitudinal slot, the cylinder being so positioned over thedischarge end of the supply box that the lifted edge of the uppermostsheet is forced to slip into the slot as it passes by and is furtherlifted by an edge of the slot, at least one counter roller beingprovided which cooperates with the hollow cylinder to pick up the sheetedge and remove the sheet from the box.

3. The device according to claim 2, wherein the curved bottom of thesupply box is convex only in the region near the discharge end andconcave for the remaining part.

References Cited UNITED STATES PATENTS 2,088,856 8/1937 Heiland 22l89EVON C. BLUNK, Primary Examiner W. S. CARSON, Assistant Examiner US. Cl.X.R.

